iommu/arm-smmu: Check for num_context_irqs > 0 to avoid divide by zero exception (44a08de2) · Commits · 戴 / test

With the right (or wrong;-) definition of v1 SMMU node in DTB it is possible to trigger a division by zero in arm_smmu_init_domain_context (if number of context irqs is 0): if (smmu->version == 1) { root_cfg->irptndx = atomic_inc_return(&smmu->irptndx); => root_cfg->irptndx %= smmu->num_context_irqs; } else { Avoid this by checking for num_context_irqs > 0 when probing for SMMU devices. Signed-off-by:

Andreas Herrmann <andreas.herrmann@calxeda.com> [will: changed to dev_err on probe failure path] Signed-off-by:

Will Deacon <will.deacon@arm.com>

drivers/iommu/arm-smmu.c

+4 −5

Original line number	Original line	Diff line number	Diff line
	@@ -1798,12 +1798,11 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev)
	smmu->num_context_irqs++;		smmu->num_context_irqs++;
	}		}

	if (num_irqs < smmu->num_global_irqs) {		if (!smmu->num_context_irqs) {
	dev_warn(dev, "found %d interrupts but expected at least %d\n",		dev_err(dev, "found %d interrupts but expected at least %d\n",
	num_irqs, smmu->num_global_irqs);		num_irqs, smmu->num_global_irqs + 1);
	smmu->num_global_irqs = num_irqs;		return -ENODEV;
	}		}
	smmu->num_context_irqs = num_irqs - smmu->num_global_irqs;

	smmu->irqs = devm_kzalloc(dev, sizeof(smmu->irqs) num_irqs,		smmu->irqs = devm_kzalloc(dev, sizeof(smmu->irqs) num_irqs,
	GFP_KERNEL);		GFP_KERNEL);

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